Heat exchange unit



P 1951 c. A. BOWSHER 2,568,984

' HEAT EXCHANGE UNIT Filed Aug. 11, 1944 3 Sheets-Sheet 1 I INVENTOR 6mm? ,4. Joya/5e ATTORNEY p 1951 c. A. BOWSHER 1 2,568,984

HEAT EXCHANGE UNIT Filed Aug. 11, 1944 s Sheets-Sheet '2 .E. 4iuwwwwwmu IlllliHIHIMIIHIIIIMHIHDHIIHIIIIIIHIHIIIIHIHIHIIHIIIIHIIIIIHI 4 INVENTOR (visa-e 4 flak/maze ATTORNEY I Patented Sept. 25, 1951 HEAT EXCHANGE UNIT Chester A. Bowsher, Dayton, Ohio, minor to United Aircraft Products, Inc., Dayton, Ohio, a corporation of Ohio Application August 11, 1944, Serial No. 549,018

7 Claims. 1

Thi invention relates to the core structure of 011 temperature regulators and like devices, and particularly to a baflle for use therein and to methods of producing the baffle.

The invention has special reference to oil temperature regulators as used in aircraft. The core structures of such devices are made up of an assembly of stacked rows of heat exchange tubes, the ends of the tubes being expanded in order that the medial portions thereof will be spaced apart for a flow therearound of the oil to be cooled or heated. The tube ends preferably have a hexagonal shape permitting interfitting. The tube assembly is partitioned by baffles having the form of substantially flat plates, supported by and between adjacent rows of heat exchange tubes. In constructing the core, since hexagonal tube ends cannot contact the baflle and at the same time interfit with the surrounding tubes, it has been the practice to utilize pentagonal ended tubes in those rows of the assembly next to the battles. The pentagonal tubes have one broad surface for contacting the flat baflle plate and have narrower surfaces .complementary to corresponding surfaces on adjoining pentagonal tubes and to the surfaces on the hexagonal tubes. So that the medial portions of the pentagonal tubes may be spaced from the baflle, it further has been the practice to mount on the ends of the baffle lifts or spacing strips on which the tube ends rest.

A general object of the invention is to simplify the task of assembling the core of an oil temperature regulator.

The invention further has as its object elimination of the necessity for using more than one type of tube in the main body of the core, and further contemplates that the spacing strip at each end of the bafile shall perform the dual function of a spacer and of a mount complementing adjacent polygonal ended tubes.

In carrying out the objects of the invention the ends of the baflle are given, either directly or through the medium of the spacing strip, a corrugated formation complementing the shape of the tube ends. Accordingly, in assembling the core only hexagonal ended tubes are needed,

those lying next to the baffle interfitting with the battle and with each other. Alternative methods of providing corrugations at the ends of the baffle are contemplated. By one method the spacing strip is preformed with two series of corrugations extending along the longitudinal edges thereof, and then the strip is folded and slipped onto the end of the ballle in such manner that one series of corrugations is on the top side of the baflle and the other series is on the underside thereof. By the other method, the spacing strip is folded and put on the baflle as a flat blank. Then, as a subsequent operation the complete assembly comprising an end of the baflle and its enfolding spacer is crimped to a corrugated form.

Other objects and structural details of the invention will appear from the following description when read in connection with the accompanying drawings, wherein:

Fig. 1 is a view in perspective of an oil tem-' perature regulator containing a core structure assembled in accordance with the present invention, a part of the core being broken away and.

the manifold head being shown in longitudinal section;

Fig. 2 is a fragmentary view of a section of the regulator core, viewed in side elevation;

Fig. 3 is a developed view of the spacer blank, showing it after it has been corrugated but before being folded;

Fig. 4 is a view in cross section, taken along the line 4-4 of Fig. 3;

Fig. 5 is a detail view in top plan of the spacer blank folded preparatory to being slipped onto the baflle;

Fig. 6 is a view in cross section, taken along the line 6-6 of Fig. 5;

Fig. 7 is a detail view, looking into the open end of the spacer blank, indicating the relation of the heat exchange tubes, and the baflle with respect to the spacer;

Fig. 8 is a view in cross section, taken along the line 8-8 of Fig. 7

Fig. 9 is a detail plan view of a bafile constructed in accordance with this invention;

Fig. 10 is a side view of the baille of Fig. 9;

Fig. 11 is a detail view in top plan of a spacer, indicated as mounted on the bafile in accordance with a preliminary step of an alternative method, the corrugations being not yet formed;

Fig. 12 is a view in cross section, taken along the line l2--l2 of Fig. 11;

Fig. 13 is a view similar to Fig. 11, showing the baflle and spacer crimped in accordance with a later step of the alternative method;

Fig. 14 is an end view of the crimped spacer and baflle, looking into the open end of the baflle and taken substantially along the line I l-I4 of Fig. 9; and V Fig. 15 is a view in cross section taken along the line l5--l5 of Fig. 14.

Referring to Fig. l, the invention is disclosed in connection with an oil temperature regulator of the class wherein a cylindrical shell ll encases a core made up of a plurality of longitudinally extending spaced partitions 2i and heat exchange tubes 22 filling the spaces between the partitions. The ends of the tubes 22 are expanded to a hexagonal shape and are adapted to interflt, that is, to occupy a nested relation with respect to each other. The arrangement is such that at the opposite ends of the core the tubes present a closed front while intermediate their ends, within the shell ll, the tubes are spaced apart and define a maze for the passage of the oil which flows to and from the core through radial openings in the shell. To hold the tubes 22 and the partitions 2i in assembled relation and as a seal against the escape of oil from the core, the tube ends are secured to each other and to the partitions by a soldering operation. Similarly the core is rigidly connected to the inner surface of the shell by means constituting a seal and a bond. The tubes 22 are open throughout their lengths for the etherethrough of a coolant which may be fluid in any form. conventionally, oil temperature regulators for aircraft are disposed in an air stream which passes through the core tubes, cooling the tubes and thereby the oil in the shell.

Secured to the outer surface of the shell I. is a flange 22 the undersurface of which has a channel 24 overlying a series of tubular conduits 25 which extend vertically into the core of the regulator and have their outer ends just-outside the shell within the flange channel 24. The inner ends of the tubular conduits 28 terminate in a header chamber 22 oppositely disposed with respect to the flange 23 and formed within the shell I! through the cooperation of end sections 21 (one shown) and a cover plate 2|. Openings 29 in the plate 2| communicate the chamber 28 with the regulator core. Thus, oil directed to flange channel 24 may enter the tubular conduits 2i and be conveyed thereby to header chamber 26 from whence it may pass through openings 29 into the regulator core. Under theinfluence of continuously applied pressure the oil may progress through the core back toward the flange 22 and in so doing contact successive air flow tubes 22 and be cooled. The partitions 2i serve as baiiies for the oil and have end openings (later to be described) to permit the passage of oil therethrough, successive baflies being reverselv arranged in order that the oil will be caused to move in a tortuous path from end to end of the cor'e. The exit from the regulator core is defined by radial openings 2| in shell I! (Fig. 2) beneath the flange 22 and registering with passages 22 therein. The passages 32 are defined by a lon itudinal rib 32 which occupies a position astride one end of the series of tubular conduits 2| and constitutes an extension of channel 24.

The flange 22 is formed with three vertical ports 24, I and 2. Ports I4 and 35 open into channel 24 while port ll communicates with the outlet passages 22.. In order that the flow of the oil through the regulator may be controlled in accordance with the temperature and viscosity conditions thereof, there customarily is mounted on the flange 23 a manifold head embodying valves constructed and arranged to compel the oil to fiow through the regulator core or to permit a flow in by-passing relation to the core-a byflow being initiated when the oil is not in need of cooling or when congelation in the core interferes with the flow therethr'ough in a manner tending objectionably to raise the pressure 4 in the system. Any known manifold head for performing these functions may be used in conjunction with the core construction here disclosed. The manifold head illustrated is one disclosed and claimed in a prior patent application by Walter H. 'Geddes and Philip W. Serial No. 514,800, filed December 14, 1943, now Patent No. 2,449,696, dated September 21, 1948. Briefly described, the manifold head comprises a body I having an inlet" and an outlet 8| on one side thereof. To'the inlet 22 is connected a line through which heated oil flows under pressure after its passage through the engine. To the outlet II is connected a line returning the cooled oil to the reservoir where it is held and withdrawn as required for re-use in the engine. Inlet ll communicates directly with the outlet 22 by wayofaportll andchamberflandfurther communicates by means, including a port 0, with the flange port 84. The outlet ll is connected through chamber 42 and by way of'a check valve controlled port with a chamber ll overlying the flange outlet port It. Chamber ll also is connected through a port 40 with a chamber 41 overlying flange port II. A pair of temperature and pressure responsive valve assemblies II and 40 control the flow of the oil through the several described ports and passages. When the oil first enters the regulator at 20, if it is under a surge pressure or is not in need of cooling it is allowed to pass through port ll into chamber 42 and is discharged from the outlet ll. As the temperature of the oil rises, a response is initiated in the valve assembly ll to the extent thatportllisclosedandportllisopened whereupon the oil stream is cut of! from direct communication with the outlet 2| and is directed by way of flange port 24 into the channel 24. From the channel 24 the oil may pass through the tubular conduits 2' to header chamber 2. and the regulator core, or it may pass through flange port II to manifold head chamber 41 and thence through port 48, chamber ll and port 44 to the outlet 32. So long as the port 40 remains open the easiest path of flow is through this port to the outlet rather than through the tubular conduits 2i and the tortuous cooling e of the regulator core. Accordingly, most of the oil by-passes the regulator core by flowing to the outlet through port 40 until a further rise in temperature causes a response in valve assembly 49 resulting in the closing of port ll. The entire fluid flow then is compelled to pass from flange channel 24 downward through the tubular conduits 25 to chamber 2| and from there out the opening 2! to the regulator core from which it subsequently is discharged by way of shell openings 2i and flange passages 82.

Considering with greater particularity the construction and manner of assembly of the regulator core, such core perferably is assembled in a jig or fixture prior to mounting it in the shell II. There first is assembled in the jig end sections 21 and cover plate 20 comprising the header chamber 20. The cover plate 2| is'formed, in addition to the openings 20, with a longitudinal row of holes adapted to receive the inner ends of the tubular conduits 2|. Accordingly, after the header section is assembled two or more uide rods are inserted in the longitudinal row of holes in cover plate 22. Following this. the heat exchange tubes 22 are laid in the fixtures on top of the coverplate 20 and on opposite sides or the guiderods. Thetubesarestackedoneuponanother until a predetermined number of rows is the core into silver solder or the like.

' conduits 25 pass.

obtained whereupon a partition 2| is slipped over the guide rods and allowed to rest on the stacked tubes, the partitions 2| -being formed with a longitudinal row of holes similar to that in cover plate 28 in order to accommodate the tubular conduits 25. The laying in of a partition 2| completes the assembly of one core section and the process above described is repeated to produce successive sections of the core. When the core is completed the assembly is made into an integral whole, preferably by dipping the ends of When the structure is rigid the guide rods may be removed and replaced by the tubular conduits 25. By reason of the presence of the guide rods, while assembling, a central channel through the core is defined. This channel is closed at its opposite ends by bars 5| having a U shape in cross section wall of the shell, and, as shown in Figs. 2, 9, and

10, there may be formed on the edges spring tips 52 which bridge the slight space between the core and the shell and inhibit circumferential oil seepage. In the center of the partition or baflle is a row of openings 53 through which the tubular Aligned with the openings 53 and at the opposite ends thereof are recesses 54 adapted to receive the channel closing bars 5i. At one end of the baflie are transverse openings provided for the flow of oil from one core section to another. These include a pair of similar openings 55 on opposite sides of the row of holes 53 and further include openings 56 which are cut through the longitudinal edges of the baiile. In front of the openings 55 and 56 are transverse beads 51 acting as dams to prevent channelling of the 0. streams as they emerge from-the baflle openings.

The openings 55 and 56 are separated by narrow neck portions 58 serving as links between the main body of the baflle and a continuation thereof beyond the transverse oil openings. The ends of the baflie are slightly off-set with respect to the body portion thereof, and are divided by the recesses 54 into separated projecting portions. On each projecting portion is a spacer element 59. Each element 59, as shown in Figs. 3 and 4, is a rectangular strip of stock which, according to one method of practiing the invention, is preformed with corrugations extending toward the center thereof; there being two series of corrugations on the strip, one extending along each longitudinal edge thereof. The conformation of the corrugations in the spacer 59 is such as to complement the hexagonal form of the ends of tubes 22. In mounting the spacers 59 on the baffle, preformed strips like that shown in Fig. 3 are folded along the uncorrugated center line thereof and are slipped onto the projecting end portions of the baflle in such manner that one series of corrugations is on the top side of the baiiie and the other series of corrugations is on the underside thereof (see Figs. 5 and 6). In asssembling the core, the corrugations on the undersurface of the spacer interflt with the ends of the tubes of the top row of the core section aecaoaa.

'with each other. It will be observed that in this form of the invention the peaks and valleys of the two'series of corrugations are opposed to each other. The effect, as seen in Fig. 7 is that the inwardly peaked portions contact and grip the battle.

An alternative method of mounting the spacer elements on the baflle is shown in Figs. 11 to 15. As seen in Figs. 11 and 12, strips 59a like those used in the first described method are folded, without being preformed, and are slipped as flat blanks onto projecting portions of a baflle 2la. Following this step, the entire end of the baflie is placed in a press or the like and the composite end, comprising the projecting portions of the baflie and their enfolding spacer elements, is crimped and caused to assume the form seen in Figs. 13 to 15. In the alternative method, since the baflle is crimped with the spacer, the peaks and valleys of the upper and lower spacer corrugations and of the baffle are parallel, and close fitting, all being squeezed to the same conformation and into a firm, secure unit.

What is claimed is:

1. In an oil temperature regulator or the like. a casing, inlet and outlet openings in said casing for the oil or other fluid to be passed therethrough, a plurality of heat exchange tubes in said casing arranged for the flow of said oil or other fluid therearound and for the passage of another fluid therethrough, said tubes having ends expanded with respect to the medial portions thereof and being assembled in stacked rows with their ends in nested relation, one or more baiiies disposed as partitions in said tube assembly with at least one end of the baille lying between the expanded ends of tubes of adjacent rows at one end of the tube assembly, and a spacing clip on said end of the bafile corrugated to provide on the upper and lower surfaces of the baiile formations complementing and receiving the expanded ends of said tubes.

2. An oil temperature regulator, comprising a casing providing oil inlet and outlet openings, a plurality of heat exchange tubes within said casing, said subes being assembled in stacked rows for the flow of oil therearound and for the passage of a second fluid therethrough, one or more baffles longitudinally disposed in Said tube assembly as partitions and having lengths approximately co-extensive with said tubes, each said bafile having the form of a flat plate the ends of which lie between the ends of adjacent rows of tubes, and a spacing clip on the ends of each said plates formed with corrugations complementing and receiving adjacent tube ends.

3. An'oil temperature regulator, comprising a casing providing oil inlet and outlet openings, a plurality of heat exchange tubes within said casing having ends expanded with respect to the medial portions thereof, said tubes being assembled in stacked rows for the flow of oil therearound and for the passage of a second fluid therethrough, one or more baffles longitudinally disposed in said tube assembly as partitions and having lengths approximately co-extensive with said tubes, each said baflies having the form of a fiat platethe ends of which lie between the ends of tubes of adjacent rows, and a spacing clip folded onto the ends of each said plates and corrugated to provide on the upper and lower surfaces of the baiiie formations complementing andreceivingtheexpandedendsofsaidtubes.

4. An oil temperature regulator, comprising a casing providing oil inlet and outlet openings, a plurality of heat exchange tubes within said casing assembled for the flow of oil therearound andforthepassageofasecondfluidtherethrough, the ends'of said tubes being expanded toapolygonalshapeandoccupringanested relationwithrespecttoeachotherwherebythe medial portions of said tubes are spaced apart, oneormorebaiiieslongitudinallydisposedinsaid tube assembly as P tions, each said baflles having an end portion approximately coincident withoneendofsaidtubeassembly,andaspacing clip on the said end portion of the bailie formed with corrugations complementing and receiving the expanded ends of adiacent tubes.

5. An oil temperature regulator, comprising a casing providing oil inlet and outlet openings, a plurality of heat exchange tubes assembled in said casing in stacked rows for the flow of oil therearouad and for the passage of a second fluid therethrough, said rows being interrupted at a common point along their lengths to deflne a channel through the assembly, closures for the ends of said channel, one or more baiiies disposed in said tube assembly as partitions and having lengths approximately co-extensive with said tubes, each said baiile having the form of a list plate the ends of which lie between the ends of tubes adjacent rows, recesses cut in the ends of each said plates receiving said channel closures whereby each end of said plate is in effect formed with separated projecting portions, and a spacer element enfolding each of said projecting portions corrugated to provide formations complementing and receiving the ends of ad- Jacent heat exchange tubes.

6. A heat exchange unit of the class described. comprising a supporting shell, a plurality of flat baiiies axially arranged in said shell in spaced relation to one another, each said baflies having an opening adjacent one end thereof and adjacent baflles being inversely arranged whereby the interior of said shell is formed into a tortuous fluid flow passage, a bundle of open-ended tubes disposed in rows parallel to said baiiies and having ends expanded to a polygonal shape, said expanded ends interfltting for a uniform spacing of the rows of tubes establishing a predetermined resistance to fluid flow through said tortuous and extending transversely across said shell, inlet means to said tortuous fluid passage communicating with the opposite end of said canduit means, said tortuous passage communicatinl at its 0990!! end with said shell 00M, and

spacer elements crimped onto the ends of mid baiiies for forming an extra spacing of an occasional row of said heat exchange tubes to provide occasional enlargements of said tortuous fluid flow passage axially of said shell and parallel to said baiiie means.

Cm A. BOWBHIR.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATE PATENTS 

